Birth Control 101: Emergency Contraception

Depending on the brand (more on that later), you can take emergency contraception up to five days after unprotected sex, but the sooner you take it, the more likely it is to work, Hill-Besinque says. Fewer than one in four women will have minor side effects such as nausea or cramps for the first 24 hours, but most are able to go about their day with no problems.